Reference Manual

HOW TO use NAT32 to limit selected traffic through an external Router.

Problem

You have a DSL Router or a Cable Modem Router (or even just a PC running
Windows ICS) to which your private machines send their Internet traffic.
Some machines are using too much bandwidth resulting in poor network
throughput for the other machines. You would like to limit throughput for
some particular machine or for some particular applications.

Solution

Run NAT32 on one machine and configure it to use just the private LAN
Adapter. Then add the following route to the NAT32
Routing Table:

That will make the machine send its Internet traffic to NAT32 at
192.168.0.254. NAT32's Administration feature can
then be used to limit the outgoing traffic of the machine to some reasonable
value. Alternatively, NAT32's Filter feature can be
used to delay specific traffic from the machine.

Even though traffic from the Internet to the machine will still
arrive directly from the external Router, NAT32 will have slowed down the
outgoing traffic and thus reduced the total bandwidth usage.

To restore the original gateway the machine was using, enter the commands:

The first command turns off the NAT32 DHCP Server, as most external
routers already run a DHCP Server.
The second command puts NAT32 into a routing-only mode in which no
mappings or translations of any kind are performed.
The third command adds a default route to the NAT32 routing table so
that NAT32 will forward all incoming Internet traffic to the external router.
This traffic is forwarded without modification and no port mapping or address
translation is performed.
The fourth command turns on NAT32 Administration. You can then open the
NAT32 Admin window and apply a desired bandwidth limit or packet transmission
limit to the private machines that choose to communicate with the Internet
via NAT32.
Alternatively, a filter like the following could be used to slow down all
FTP transfers running on the machine: